Introduction
Rubiaceae
Asclepiadaceae
Nepenthaceae
Bromeliaceae
Orchidaceae
Polypodiaceae
Ecology and
evolution
Cultivation
References
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Polypodiaceae
Two genera of ferns, Solanopteris and Lecanopteris,
are known to be ant-fed, ant-house epiphytes. The potato ferns, Solanopteris, are found
in tropical America, while Lecanopteris are from Asia. In Solanopteris, tuber-like structures form as off-shoots
of the long thin rhizome. Ants may hollow out and eat the sugary contents of the tubers
(Huxley, 1980), but hollow tubers observed in cultivated ferns indicate that the cavities
will also form in the absence of ants. In any case, the hollow tubers form nest sites for
ant colonies.
In southeast Asia, the genus Lecanopteris grows in
much the same habitat as the rubiaceous ant-plants (Janzen, 1984; Gay et al., 1993). Like
Dischidia, Lecanopteris species display a variety of ant-house structures
(Gay, 1993a; Walker, 1985). Lecanopteris mirabilis has the simplest domatium, a
solid, arching rhizome that hugs the tree branch. Ants live in the hollow between the rhizome
and the bark. Lecanopteris sarcopus has a solid rhizome with hollow side-branches.
The hollow, creeping rhizomes of other species have galleries of varying complexity. The rhizomes
do not have natural openings; Ants gain access when older portions die back. Use of radioactive
tracers has demonstrated that nutrients deposited in the
rhizome hollows by the ants are incorporated into the fern's tissue (Gay, 1993b).
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